Fluoroelastomers are cured or crosslinked and generally are tolerant to high temperatures and harsh chemical environments. They are particularly useful as seals, gaskets, and molded parts in systems that are exposed to elevated temperatures and/or corrosive materials. For sealing applications that require resistance to the most extreme conditions, perfluorinated elastomers are used. Such parts are used in applications such as automotive, chemical processing, semiconductor, aerospace, and petroleum industries, among others.
Fluoroelastomers often include a cure-site component to facilitate cure in the presence of a curative or catalyst. One class of useful cure-site components used in perfluoroelastomers includes nitrile group-containing monomers, for which organotin catalysts have been used as curing components. However, such catalysts can leave undesirable extractable metal residues in the cured product and are undesirable for environmental reasons. Ammonia-generating compounds have also been used as a cure system component in fluoroelastomers, but these cure systems lack the desired level of rheology control during processing. Fluoroalkoxy onium containing catalysts were developed to address improved compression set performance. However, these catalysts still lack the desired level of rheology control (i.e. premature curing during processing, often referred to as “scorch”) during processing unless additional steps were taken to react these catalysts with additional materials. Surprisingly, it has now been found that the additional steps to reduce scorch in fluoropolymer compounds made using these catalysts are obviated by eliminating the use of hydrocarbon containing alcohol when preparing catalyst compounds or removing the hydrocarbon containing alcohol from the catalyst compounds.